| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.29 | 0.38 | 0.15 |
| 2024 | 0.35 | 0.43 | 0.21 |
| 2023 | 0.23 | 0.58 | 0.06 |
| 2022 | 0.53 | 0.63 | 0.47 |
| 2021 | 0.48 | 0.52 | 0.46 |
| 2020 | 0.55 | 0.69 | 0.44 |
| 2019 | 0.77 | 0.92 | 0.64 |
| 2018 | 0.92 | 1.1 | 0.73 |
| 2017 | 1.19 | 1.29 | 1.09 |
| 2016 | 1.23 | 1.38 | 1.16 |
| 2015 | 1.28 | 2.02 | 0.95 |
| 2014 | 0.94 | 1.17 | 0.82 |
| 2013 | 0.93 | 1.17 | 0.85 |
| 2012 | 1.02 | 1.28 | 0.77 |
| 2011 | 1.38 | 1.7 | 1.18 |
| 2010 | 1.37 | 1.6 | 1.15 |
| 2009 | 1.57 | 2.97 | 1.19 |
| 2008 | 2.86 | 5.44 | 1.25 |
| 2007 | 4.29 | 6.82 | 2.66 |
| 2006 | 2.29 | 2.73 | 1.77 |
| 2005 | 0.39 | 1.87 | 0.04 |
| 2004 | 0.08 | 0.11 | 0.06 |
| 2003 | 0.08 | 0.1 | 0.07 |
| 2002 | 0.08 | 0.11 | 0.07 |
| 2001 | 0.1 | 0.16 | 0.04 |
| 2000 | 0.03 | 0.04 | 0.02 |
| 1999 | 0.02 | 0.03 | 0.01 |